Indiana State Board of Animal Health

Pseudorabies (PRV) is a highly contagious infectious disease of swine caused by a herpes virus. As the only primary hosts, swine can contract the disease, recover, and remain carriers.

Carrier animals with PRV do not shed the virus on a continual or daily basis. Once the acute infection is over, the virus becomes dormant within the body. The carrier animal may never again shed the virus or may shed virus when the animal is stressed, i.e., chilling, moving, breeding, farrowing, or any other type of stress. That is why herd cleanup plans must address all factors that cause stress.

Other species of animals are considered dead-end hosts, that is, if they become infected they die.

Species

Resistance to Infection

Outcome of Infection

pig

low

variable

dog

high

fatal

cat

high

fatal

cattle

moderate

fatal (with exceptions)

sheep

low

usually fatal

raccoon

moderate

fatal

opossum

high

fatal

rat

high

fatal

mouse

high

fatal

other wildlife

?

fatal

Environmental ContaminationOutside of a host animal's body, the virus is very susceptible to the elements. PRV cannot live long without some degree of protection. The virus moves within the herd through direct animal-to-animal contact, or indirectly via respiratory excretions. Snotty nasal discharge can stick to panels, workers' clothing, feed, bedding, boots, trucks, and other equipment. Non-infected hogs can pick up the disease after contacting such contaminated items.

Research at Iowa State University on the environmental survivability of the PRV virus shows:

PRV is very susceptible to pH levels below 4 and above 9.

Survival is temperature dependent.

The virus can survive only a few hours on clean concrete or mixed in dirt.

The PRV virus can survive up to three days on plastic and steel.

Two days is the virus' survival time in manure and lagoon water.

Whole corn can sustain the virus up to four days.

The PRV virus mixed with body excrement can survive on the soil for up to six days.

Under optimal pH and temperature conditions, some virus particles may survive as long as 40 days to 120 days. However, these conditions are unlikely to exist.

BiosecurityManagement procedures that revolve around sound biosecurity practices are very important in all disease control programs. Maintaining a strict biosecurity program is the best way producers can protect their investments in livestock.

At a minimum, every swine operation should:

Isolate and retest of all incoming livestock.

Minimize and control of human traffic into and within the herd. People should not move indiscriminately from known infected areas of a unit throughout the rest of the operation. This rule applies to all maintenance workers, plumbers, electricians, etc., as well as employees.

Control of feed supply sources and the feed delivery processes.

Control wildlife, rodents and pests on the site.

Consider geographical location when planning a new swine production unit.